The management of a patent portfolio involves multiple stages. Initially, a decision is made as to what inventions are worth the investment of filing a patent application. Then, each filed patent application goes through prosecution with the patent office. Finally, for each patent that is allowed, maintenance fees must be paid at a variety of intervals to keep the patent in force. At any stage during its life, a patent application or patent may be assigned by the inventors to an assignee, or be assigned from one assignee to another. The assignee may be an individual or a corporation.